Reflex spasm of the diaphragm (6)
I believe the answer is:
hiccup
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">reflex spasm of the diaphragm</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for hiccup that I've seen before include "Involuntary glottal closure" , "Temporary setback (colloq.)" , "Snag" , "Minor setback" , "Minor difficulty" .)